This invention relates generally to coin analyzers or discriminators and, more particularly, to coin analyzers that are capable of distinguishing among a plurality of coins. The invention is useful with various coin-operated machines; for example, video games, car washes, clothes washers and dryers, coin counters, and the like.
The invention in commonly assigned U.S. Pat. Nos. 4,884,672 and 5,056,644 provided the first commercially successful coin analyzer that was capable of detecting two coins, or a coin and token. In such commonly owned patents, a sample coin holder held two coin denominations or a coin and token adjacent to associated sample coin coil assemblies. A test coin coil assembly was located at a coin path. A circuit compared the effect on the magnetic field at the test coin assembly with the sample coin coil assemblies in order to determine when a match occurred between a test coin and one of the sample coins. The coin analyzer disclosed in these commonly assigned patents utilized analog circuitry to operate a kicker coil to accept a valid coin and in order to provide a credit indication of the amount of valid coins accepted.
Since the introduction of the Slug Buster II coin analyzer, which embodied the invention in the '672 and '644 patents, other multiple coin analyzers have been developed. These other coin analyzers typically utilize a microprocessor in combination with a test coil assembly and other input circuitry. The microprocessor stores characteristics of various coin denominations. When a coin is inserted in the coin path, the output of the test coil is applied to the microprocessor through the input circuitry. The microprocessor attempts to identify a match between the characteristics of the test coin and those stored within the microcomputer. If a match occurs, then a particular coin is deemed to have been identified. Such coin analyzers typically have a learning mode in which the coins to be identified are juxtaposed with the test coil while the microprocessor stores the parameters of each denomination coin.
One difficulty arises with coins of very similar characteristics. For example, the United States Mint introduced the Susan B. Anthony dollar coin which was made from a five-layer clad blank. The United States quarter is also made from a five-layer clad blank similar to that from which the Susan B. Anthony dollar is made. As a result, commercially available coin analyzers are incapable of accurately discriminating between a Susan B. Anthony dollar and a United States quarter. Other countries have such coins of similar properties. Also, coins from one country may have similar properties to a coin of another country. The inability of coin analyzers to distinguish between two coins having similar properties is a serious deficiency that heretofore has created a long-felt need in the art of coin analyzers. The present invention satisfies this long-felt need.